A bug report complained that Izchak is identifiable when the hero is
hallucinating. That's true but it wasn't particular to him; all shop
transactions were giving accurate shk name regardless of hallucination.
This is a quick fix that avoids changing shk message handling: pick some
shk name at random each time one is used. I didn't intend for it to also
force Izchak to use the general chat response instead of his set of special
messages, but that ends up happening due to randomized name not matching
his, so you really can't recognize him when hallucinating anymore.
The almost never seen names now have a chance to come into play....